Basics of Computers - Part 2

CLASSIFICATION OF COMPUTER : Computers can be classified on purpose, components and size

1. ANALOG COMPUTERS : Analog computers are computer that measures physical quantities (eg. Temperature, length, pressure, Whether reports etc...) and convert them to numeric values. It is used mainly for scientific & engineering purpose.
   
   
2. DIGITAL COMPUTERS : Digital computers are used for mathematical operations such as (eg . addition ,subtraction, letters, symbols)
   
   
3. HYBRID COMPUTERS : The features of analog and digital computer are combined to create a hybrid computing system. The doctors to measure hearts beats SIZE mostly use hybrid computers.

All digital computer store numbers, letters and other characters in coded form. The code used to represent characters in the binary code - i.e. a code made up of binary digits or bits. Every character is represent by a string of "Os" and ""Is" - the only digits found in the binary numbering system. When data is types into a computer the keyboard convert each keystroke into a binary character code. This code is then transmitted to the computer, when the computer transmits the data to the - printer or the screen, or to the disk, each individual character is communicated in binary code. It is then converted back to the specific character while displaying or printing the data. One 'Bit1 is a short of Binary Digit. A collection of 8 bits is known as a BYTE and half of byte i.e. a collection of 4 bits is known as a NIBBLE 1 Byte = 8 Bits; 1 Kilobyte (KB)= 1024 Bytes; 1 Megabyte (MB)= 1024 KB; 1 Gigabyte (GB) = 1024 MB

Note :- Every character you type occupies 1 byte, Every Space occupies 2 bytes and every Enter you hit occupies 2 bytes.

TYPES OF STORAGE SYSTEM

1. INTERNAL STORAGE :-

RAM :- (Random Access Memory ).Where programs arid data are held during processing temporarily. Data stored in the RAM is lost when either the machine is switched off.

ROM :- (Read Only Memory). Where permanent instructions or data are held. The ROM does not require a continuous supply of power to retain it contents.

2.EXTERNAL STORAGE:-

HARD DISK : Hard disks are a collection of/ pack of diskettes, known as platters, made of aluminum, with their surface being coated with iron oxide joined together to form a cylinder. They have more storage capacity and speed than floppy disks.

Floppy Disk : Floppies are made of Mylar plastic coated with magnetic oxide. The flexible material is cut into circular pieces.5 1/4" or 3 1/2" in diameter.

The other external storage devices are Compact Disk(CD), Digital Video Disk (DVD) and Pen Drive having different storage capacities.